SUMMARY The Surgical Idiopathic Intracranial Hypertension Trial (SiihTT) chaired by Dr. Michael Wall, is a randomized treatment trial to compare the efficacy of acetazolamide, optic nerve sheath fenestration and ventricular peritoneal shunting on moderate to severe visual field loss due to idiopathic intracranial hypertension (IIH). The SiihTT Resource Center (RC) will manage the activities of three experienced Reading Centers, which will train and certify sites, and perform quality control of essential study data. - visual fields, fundus photos of papilledema and optical coherence tomography (OCT) of the optic nerve and retina. Perimetric mean deviation (PMD) is the principal measure to determine change in IIH status, particularly worsening and the effects of therapy. OCT images will provide continuous variable measures of swelling and loss in the optic nerve head, peripapillary retina, and macula that will complement PMD and photos for assessing malfunction of surgical intervention and safety. Measuring ganglion cell layer thinning will be used to determine structural neuronal loss even in the setting of persistent papilledema. Clinic Sites will perform testing by technicians, who are certified by the Reading Centers, according to the protocol established by each Reading Center. Each Reading Center will oversee all aspects of these important measures. The RC will provide supervision and facilitate communication between Sites, Study Committees, DCBC, and the Reading Centers to address quality control and data organization for evaluations. The RC will utilize monthly teleconferences and review of Reading Center and DCBC reports to coordinate study activities. This approach will result in optimal integration and high quality images and visual field data collection used to test the study aims.